title: Three-axial strain controlled testing applied to bone specimens from the proximal tibial epiphysis.
abstract: Reproducibility of the determination of Young's modulus and energy absorption along the three axes of trabecular bone cubes was analysed by non-destructive compression to 0.5% strain using different testing protocols. These protocols included testing with and without pre-conditioning to a viscoelastic steady state, and different orders of test directions. Reproducibility of conditioned tests was generally better than that of non-conditioned tests. No major effect of changing the order of the test direction was found. Three-axial conditioned testing of cubes from the proximal tibial epiphysis of five humans revealed a global transverse isotrophy while most cubes showed orthotropy. The ratio between stiffness along the long axis of the tibia and the stiffness in the transverse plane was 3.7 +/- 0.4 (mean +/- 2 SE). The corresponding ratios for elastic energy storage and viscoelastic energy dissipation were 2.5 +/- 0.2. There was no difference between the relative energy loss during a testing cycle (loss tangent) in the three axes.
authors.affiliation: Biomechanics Laboratory, Orthopaedic Hospital, University of Arhus, Denmark.
authors.forename: F
authors.initials: F
authors.lastname: Linde
authors.forename: B
authors.initials: B
authors.lastname: Pongsoipetch
authors.forename: L H
authors.initials: LH
authors.lastname: Frich
authors.forename: I
authors.initials: I
authors.lastname: Hvid
mesh_terms: D000328:Adult; D004548:Elasticity; D004838:Epiphyses / Q000033:anatomy & histology / Q000502:physiology*; D006652:Histological Techniques; D006801:Humans; D008875:Middle Aged; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D013977:Tibia; D014783:Viscosity